Refining mineral oils



Patented Feli. 25,1947 Q 2,416,397 I p I REFININGMINERAL 011,8"

Norman E. Lemmon, Hammond, 1nd,, 'assignorto Standard Oil Company, Chicago, lll.',a corporation of Indiana 3 No Drawing.

This invention relates to improvements in the refining of hydrocarbon oils andin particular to improvements in the refining of white oils such as medicinal mineral oils, technical'whlte' oils, and the like, to obtain increased yields of Mind preferential oil-soluble water non-emulsiflable sulfonic compounds;

In the preparation of highly refined petroleum oils of thetype 'of insulating oils, turbine oils, technical white oils, and mineral medicinal oils,

the oils ar treated successively with a number of portions ,of concentrated or fuming sulfuric acid. A variety of sulfur-containing compounds are formed by the chemical reactions of the treating operation, including sulfonic acids,. organic esters of sulfuric acid, partial esters of sulfuric acid, etc. insoluble in the oils under the treating conditions but substantiallynon-emulsiflable with water, will 1 be, referred to as preferential oil-soluble, water non-emulsiflable sulfonic compounds," fpreferential oil-soluble, water non-emulsiflable sulfonic acids, or preferential oil-soluble, water non- Most of these compounds are relatively and separate from the oil, together with unreacted acid, as a sludge which is separated fromthe oil after each acid treatment. Someof the sulfonic acids'are. preferentially oil soluble; these remain in the oil and can be removed therefrom by neutralizing the acid-treated oil with caustic soda, caustic potash or ammonia, to form sulfonic acid soaps or sulfonates, and extracting these sulfonates from the oil by treatment with 50% to 80% aqueous alcoholic solutions or other, suitable means. Because of the characteristic mahogany color of these sulfonates they are known in the petroleum art as mahogany soaps. While the preferential oil-soluble sulfonates or sulfonic acids, hereinafter generically called sulfonic compounds, from different stocks, and by different acid treatments. as a class are all soluble in oil, they all do not behave similarly in water solubility and/or emulsibility That is, certain of the preferential oil-soluble sulfonic compounds form relatively stableemulsions with water, while other types of the preferentialoil-soluble sulfonic compounds do not form emulsions with water or are difllcultly emulsiflable with water. Thus =preferential oil-soluble sulfonic compounds obtained by treating a petroleum oil hav ing a. Saybolt Universal viscosity at 100 F. of less than. about 150 seconds, with about 3 to about 4 pounds of fuming sulfuric acid per gallon of oil Application September-28,1943, I I Serial No. 504,163

compositions. vi-Iowever',sucl' sulfonic compounds are of valuefor other-purposes, such as,- for example, as rusting and/or corrosion inhibitors in slushing or anti-rust compositions. Hereinafter and in the appended claims, sulfonic compounds of this type, which are preferentially oil-soluble emulsiflable sulfonates.

By the term water non-emulsiflable? as used herein and in the appended claims, is meant an oil-soluble sulfonic compound which doesv not pass the emulsion test, described by F. M. Archi bald in the article Analysis of petroleumoil soluble sulfonic acidsoaps," on page 611 of September 15, 1941, issue of the Analytical edition of Industrial and Engineering Chemistry.

. Inthe manufacture of white oils, the process commonly employed is the treatment of a petroleum, oil, and especially a petroleum distillate,

tomarily applied to the oil in small portions or. dumps" of about one-half pound to about one. pound of acid per gallon of oil. Thus, in prepar I ing a medicinal white oil, approximately 8 pounds oil, applied in 8 or more successive dumps, the

acid sludge being settled and withdrawn .after, each dump. Treating the oil in this manner 1 resultsin a relatively low yield of finished oil and .low yield of preferential oil-soluble, water mmor sulphonic acid v soaps.

are characterized by their ability to readily emulw my with water to give stable emulsions. These sulfonic compounds therefore, are well suited for the preparation of soluble oil compositions. I

Treating an oil of the same type as the above, or an oil having a Saybolt Universal viscosity at 100 F. above about 225 seconds with about 7,410 about 8 pounds of fuming sulfuric acid per gallon with large quantities of sulphuric acid; In general, fuming sulphuric acid of about mi /2% of H2804 equivalent is employed and the acid is cusof fuming sulphuric acid is used per gallon of emulsiflable sulphonic acids It is an object of the invention to provide a method of treating petroleum oilswith sulphuric acid which will result in a maximum yield of pref- 1 er'ential oil-soluble water non-emulsiflable sulphonicacids or sulphonic acid soaps. Another object of the invention is to provide a methodifor manufacturing white oils with fuming sulphuric acid which will give a maximum yieldof refined oil and preferentiallyoil-soluble water non-emulsifiable sulphonic acids. of the soaps thereof with a minimum acid requirement. It is another obof oil, will produce preferential oil-soluble suli fonic compounds which are substantially non- I emulsiflable with water. That is, stable emulsions with water cannot-be formed, and hence they are unsuited for use in the preparation of soluble oil ject of the present invention to provide a method of refining white mineral oils by treatment with sulphuric acid which will result in a maximum yieldiof treated oil.

.In accordance with the present invention, the foregoing objects are attained by' treating a hy-' drocarbon oil, such as petroleum oil, having a Saybolt Universal viscosity at F. above about 225 seconds, for'ex'ample, from about 250 seconds to about '1000seconds, and preferably from about 400 to ,about .800 seconds, with from about 2 pounds to about 4 pounds of concentrated sulphuric acid, preferablyfuming sulphuric acid, per gallon of oil, separating the resultant acid sludge, extracting the preferential oil-soluble water nonemulsiflable sulfonic acid or soap from the. treated oil with alcohol, removing the last traces of alcohol from the-extracted oil and retreating the oil with about 1 pound to about 3 pounds of concentrated sulphuric acid, and preferably fuming sulphuric acid, per gallon of ,oil, and again extracting the preferential oil-soluble-water nonemulsifiable sulfonic acids with alcohol from the sour oil. The alcohol extracted sour oil is then neutralized, steamed and blown bright, or alternatively extracted sour oil can be neutralized, the neutralized oil again extracted with alcohol and the oil finally blown bright and, if desired treated with clay, such as by clay percolation through a decolorizing clay such as Attapulgus clay. In applying the sulphuric acid to the oil in either the first or the second stages, the oil is preferably added in dumps of one-half pound of acid per gallon of oil. 7 I

,After the first acid treatment stage in which 2 to 4 pounds of acid per gallon of oil is employed, the preferential oil-soluble, water non-emulsifiable sulfonic acids may be extracted as such with alcohol, preferably ethyl alcohol, or they may be converted into the soap by treatment with a neutralizing agent, such as caustic soda, caustic potash or the like, and the sulfonic soaps so formed extracted from the oil with alcohol; however, after tlze second acid treatment stage the sulfonic acids must be extracted as such.

In the acid treating stages temperatures of from about 40 F. to about 250 F., and preferably from about 60 F. to about 100 F. are maintained. The contact time of the acid with the oil is preferably within the range of about 150 to 250 minutes for a treating temperature range of 60 to 100 However, a contact time as low as three to thirty minutes may be used with treating temperatures within the range of 100 to 250 F.

The extraction of the preferential oil-soluble, water non-emulsifiable sulfonic acids or the soaps thereof from the acid treated oil is accomplished preferably with alcohol of about 60% concentration and usually in the range of about 55% to about 70%, the amount of alcohol requiredfor the extraction being within th range of from about 10 gallons to about 30 gallons of alcohol per 100 gallons of oil.

The alcoholic solutions of preferential oil-soluble, water non-emulsifiable sulfonic acids or the soaps thereof from each of the alcohol extraction stages can be treated, such as by distillation, to remove the alcohol and the preferential oil-soluble, water non-emusifiable sulfonic compounds recovered. If the preferential oil-soluble, water non-emulsifiable sulfonic compounds are extracted as the acid in the first extraction stage,

the alcoholic extract from the first extraction stage may be combined with the alcoholic solution of preferential oil-soluble water non-emulsifiable sulfonic acids from the second extraction stage and the alcohol removed from the combined fractions.v The acids can then be converted to the soap by neutralization with an alkaline reagent such as caustic soda, caustic potash, or the like. If the preferential oil-soluble water non-emulsifiable sulfonic compounds are extracted as the soap, the preferential oil-soluble water non-emulsifiable sulfonic acids extracted from the second extraction stage can be converted to the soap by neutralization andthe alcoholic solutions of the 4 soaps combined. The'soaps can then be recovered by means such as distillation.

It has been found that in the first acid treatment stage, a portion of the spent acid sludge from the second acid treatment stage can herecycled and used to replace a portion of a fuming sulphuric acid normally used in the first acid- I treating stage. v v

The effectiveness of the present invention is demonstrated by the data of the following examples which are given by way of illustration and are not intended to be limitative of the scope thereof.

Eztampla-A-petroleum distillate having 9. Saybolt Universal viscosity at F. of about 233 seconds was treated with 3 pounds of fuming sulphuric acid p r gallon of distillate in /1 pound dumps. After removal of the acid sludge after the last acid dump and neutralization of the oil, it was extracted (sour) with alcohol and the last .traces of the alcohol removed from the oil by distillation. The oil was then treated with an additional 2 /2 pounds of fuming acid per gallon of distillate in /2 pound dumps and the sour oil was extracted with alcohol after removal of the acid sludge. The extracted oil was then neutralized, steamed and blown bright, The yield of finished oil and of preferential oil-soluble, water non -emulsifiable sulfonic acids recovered are given in the following Table I in comparison with the yield of oil and of mahogany acids obtained by treating the oil in the usual manner with 7 pounds of fuming sulphuric acid per gallon of distillate without an intermediate extraction step.

Table I Yield of 100% preferential oil-soluble Method Total Yiold water nou-emulsl acld/ of fi fiable sulfonic acid, dist Hate percent VOL percent on tillate 01d 7. 0 50. 3 l. 32 New 5.5 58.3 6.07

The above data show the increased yield of oil with the present invention.

The data represented in Table II below illustrate the improvements obtained by treating coastal oils of 600 seconds Saybolt viscosity in accordance with the present invention over that obtained by treating in the conventional manner. In each of. the first three tests the oil was treated with fuming sulphuric acid in two stages with an intermediate alcohol extraction after the first acid treatment stage. In test No. 1 the oil was treated first with 3 pounds of fuming sulphuric acid in /2 pound acid dumps, the oil neutralized with caustic soda and the neutralized oil then extracted with 60% alcohol to remove the preferential oil-soluble, water insoluble sulfonates. The oil was then given an additional treatment with 3 /2 pounds of fuming sulphuric acid per gallon of oil in /2 pound dumps and the sour oil extracted with 60% alcohol. In test No. 2 the distillate oil was treated first with 3 /2 pounds fum- 2 /2 pounds of fuming sulphuric acid per gallon of distillate in pound dumps. The preferential oil-soluble, water non-emulsiflable sulfonic acids were then extracted from the sour oil with 60% alcohol. In test No. 3, the oil was first treated with 4 pounds of fuming sulphuridacid per'galion of distillate in /2 pound dumps and preferential oil-soluble, water non-emulsiflable sulfonic acids extracted from the sour oil with 60% alcohol.

Table II Lbs.

8cm] Yields distillate Alcohol extraction 60- alcohol 2nd stage lst stage stage 1st stage Alkaline. Sour.

3 4.0 Sour do Conventional procccure-S lbs. acid per gallon distillate, extracted sour after total acid treat with no intermediate alcohol extraction.

I Preferential oil-soluble, water non-emulsiflable acids.

. The increased yield of preferential oil-soluble water insoluble sulfonic acids obtained by treating oils of Saybolt Universal viscosity at 100 F.

above 225 seconds by the method of the present invention is further demonstrated by data in Table III below. These data were obtained by treating an oil having a Saybolt Universal viscosity at 100 F. of about 600 seconds, and an oil having a Saybolt Universal viscosity at 100 F. of about 125 seconds withsixteen successive onehalf pounds of fuming sulfuric acid per gallon of oil, and determining the amount and type of pref erential oil-soluble sulfonic acid extracted from the sour oil after each one-half pound acid dump. v

Table III High viscosity oil Low viscosit oil g ff q Efigifii 1bs. or l 00%"sullbs. cfl sul- Hsoz assists san ers i m dist. distillate I Preferential oil-soluble, water insoluble sulfonic acids.

* Preferential oil-soluble, water soluble sulionic acids.

Conventional methods for obtaining preferential oil soluble, water insoluble suifonic compounds.

The oil was then given an additional treatment with 2 pounds of fuming sulphuric acid per above data show the large yield increase of preferential oil-soluble, water insoluble sulfonic compounds obtained by the present invention, over that obtained by treating oils by the conventional method with eight pounds of concentrated sulfuric acid per gallon of oil to obtain the same type of sulfonie compound.

As shown by the data of the above Tables I 1 well as the increased yields.

While the method of treating and purifying mineral oils herein described is well suited for accomplishing the purposes df'the Present'invention, it is not intended to. limit the invention to the specific embodiments described herein, as various modifications may be made without departing from the spirit of the invention.

I claim:

g 1. The method of obtaining increased yields of preferential oil-soluble, water non-emulsifiable sulfonic compounds from petroleum oils comprising treating a viscous hydrocarbon oil having a Saybolt Universal viscosity at 100 F. above about 225 seconds with from about 2 pounds to about 4 pounds of concentrated sulfuric acid per gallon of oil, separating the acid sludge from said treated oil, extracting perferential oilsoluble water non-emulsifiable sulfonic compounds from the acid treated oil with alcohol,

removing alcohol from the extracted oil, treating the alcohol extracted oil with from about 1 pound to about 3 pounds of concentrated sulfuric acid per gallon of oil, separatingthe acid sludge formed, extracting preferential oil-soluble water non-emulsiflable sulfonic acid from the acid treated oil with alcohol, and removing the alcohol from both alcohol extracts of the preferential oil-soluble water nonemulsifiable suifonic' compounds.

2. The method described in claim 1, in which the concentrated sulfuric acid is fuming sulfuric acid.

the concentrated sulfuric acid is applied in- /2 pound dumps.

4. The method described in claim 1, in which the preferential oil-soluble sulfonic compounds are extractedwith alcohol of fromabout 55% to about 70% concentration. 7

5. The method of obtaining increased yields of preferential oil-soluble water non-emulsifiable sulfonic compounds from petroleum oils comprising treating a viscous hydrocarbon oil having a Saybolt Universal viscosity at 100 F. of from about 250 seconds to about IOOO'seconds with from about 2 pounds to about 4 pounds of concentrated sulfuric acid per gallon Of oil, separating the acid sludge from said oil, neutralizing the acid treated oil, extracting preferential oil-soluble water non-emulsiiiable sulfonates from the neutralized oil with alcohol, removing the last traces of alcohol from the extracted oil, treating the alcohol extracted oil with about 1 to about 3 pounds of concentrated sulfuric acid 7d per gallon of oil. separating the acid sludge 3. The method described in claim 1, in which I from both alcohol extracts of the preferentialoil-= soluble sulfonic compounds. l

8. The method described in claim 5, in which the concentrated sulfuric acid is fuming-sulfuric acid. r g 7. The method of obtaining preferential oilsoluble water non-emulsiflable sulfonic com-. pounds from petroleum oils comprising treating a petroleum mineral oil distillate having a Bay. bolt Universal viscosity at 100 1". above about 225 seconds with about three pounds of fuming sulfuric acid per gallon of oil, separating the acid-sludge from the sour 'oil, neutralizing the sour oil, extracting a preferential oil-soluble water non-emulsiflable sulfonic acid soap from the neutralized oil with alcohol, freeing the oil of entrained alcohol, re-treating the three pound acid-treated oil with about three pounds more of fuming sulfuric acid. separating the acid sludge, extracting the preferential oil-soluble s I v water non-emulsiiiable sulfonic acid from the six pound acid-treated oil with alcohol and neutralizing the extracted preferential oil-soluble water non-emulsifiable sulfonic acids.

NORMAN E, LENNON.-

nmnnncns crrnn The following references are of record in me of this patent:

v UNITED STATES PATENTS Sachanen Dec. 16, 1941 

